Light projecting technologies are essential for enabling several important device functionalities. For example, structured light projection and detection components may be deployed in 3D camera modules of mobile phones for recognizing facial features (e.g., for authentication purposes, emoji generation, etc.). In such systems, projected light may reflect off the facial features of a user, and may be captured by a detector and analyzed by algorithms to “perceive” or “resolve” the topology of the user's face. Light projection technologies are also relevant to many other functions beyond facial recognition, of course, including for generating 3D point clouds for scene reconstruction (e.g., for use in modeling, virtualized environments, etc.), for computing depth or other dimensions of a real space (e.g., a mobile app used in construction or design that computes the dimensions of a room in a building), LiDAR applications, etc.
Current light projection technologies are disadvantaged, however, both for high cost, large size, low integration, and poor depth resolution of ToF based images. In particular, conventional ToF technologies rely on flood light illumination to resolve depth. That is, a flood light source is used to illuminate a target, then reflections of that flood light (off of a surface the flood light was projected onto) are captured by a ToF sensor to measure return time differences in the reflected light.
Unfortunately, the conventional use of flood light sources to illuminate a surface for ToF based measurements does not result in highly accurate depth resolution. Indeed, flood light detections are more heavily influenced by light emissions within the environment that did not originate from the projecting light source, and as a result the signal-to-noise ratio is low.
Furthermore, conventional light projection technologies do not fully utilize already available light sources to achieve the many imaging objectives that might be useful for the various functionalities noted above. Instead, conventional light systems utilize multiple projection sources to achieve their objectives. These inefficiencies impose bottlenecks for the advancement of device structure and function built on or around the light projection features. Therefore, improvements over the existing light projecting technologies are desirable for both the consumer market and the industry generally.